Shomu Bohora

KCNQ1 mutations associated with Jervell and Lange–Nielsen syndrome and autosomal recessive Romano–Ward syndrome in India—expanding the spectrum of long QT syndrome type 1

Long QT syndrome type 1 (LQT1) is the most common type of all Long QT syndromes (LQTS) and occurs due to mutations in KCNQ1. Biallelic mutations with deafness is called Jervell and Lange–Nielsen syndrome (JLNS) and without deafness is autosomal recessive Romano–Ward syndrome (AR RWS). In this prospective study, we report biallelic mutations in KCNQ1 in Indian patients with LQT1 syndrome. Forty patients with a clinical diagnosis of LQT1 syndrome were referred for molecular testing. Of these, 18 were excluded from the analysis as they did not fulfill the inclusion criteria of broad T wave ECG pattern of the study. Direct sequencing of KCNQ1 was performed in 22 unrelated probands, parents and at‐risk family members. Mutations were identified in 17 patients, of which seven had heterozygous mutations and were excluded in this analysis. Biallelic mutations were identified in 10 patients. Five of 10 patients did not have deafness and were categorized as AR RWS, the rest being JLNS. Eight mutations identified in this study have not been reported in the literature and predicted to be pathogenic by in silico analysis. We hypothesize that the homozygous biallelic mutations identified in 67% of families was due to endogamous marriages in the absence of consanguinity. This study presents biallelic gene mutations in KCNQ1 in Asian Indian patients with AR JLNS and RWS. It adds to the scant worldwide literature of mutation studies in AR RWS.

Reappraisal and new observations on atrial tachycardia ablated from the non-coronary aortic sinus of Valsalva

Aims The clinical characteristics of atrial tachycardias (AT) ablated from the non-coronary aortic sinus (NCS) are thus far described only in small series. We aimed to outline, in a large cohort of patients, the clinical, electrocardiographic, electrophysiological characteristics of this tachycardia. Methods and results We analysed data pertaining to clinical, electrocardiographic, and electrophysiological characteristics of 43 consecutive patients from an overall cohort of 441 with AT who were successfully ablated from the NCS. The tachycardias ablated from the NCS were paroxysmal (98%) and adenosine sensitive (35/35). The patients were aged 54.6 ± 12.4 years, showing female preponderance (74%). No P wave pattern was predictive of the location of ablation. Electrophysiological findings suggested a possible micro-reentrant mechanism. During tachycardia, atrial electrograms recorded in the NCS preceded the A in the His region by 10.9 ± 7.4 ms. Fractionated atrial electrograms were noted at the site of ablation in 42 patients during the tachycardia. Radiofrequency ablation terminated the tachycardia within 5 s in 88%, with thermal automaticity seen only in 3 patients. The site of ablation at the base of the NCS was adjacent to the presumed site of the retroaortic node, a remnant of the initial atrio-ventricular canal musculature. Conclusions AT ablated from the NCS is a paroxysmal arrhythmia in middle-aged women, with distinct electrocardiographic and electrophysiological characteristics. We suspect the retroaortic node to be involved in the tachycardia circuit.

Narrow complex tachycardia with ventriculoatrial dissociation--what is the mechanism?

Case Presentation A 38-year-old woman presented with recurrent sustained episodes of palpitation, each episode lasting more than 3 weeks. The symptoms were unresponsive to amiodarone 400 mg/day. Echocardiogram revealed mildly dilated left ventricle with global left ventricular hypokinesia and ejection fraction of 30%. The electrocardiogram (ECG) during palpitation showed a narrow QRS tachycardia with ventriculoatrial (VA) dissociation and mild variations in RR interval (Fig. 1A). The QRS complex during the tachycardia was relatively narrow (100 ms), and exhibited left anterior fascicular (LAF) block morphology and leftward (−45◦) axis. During sinus rhythm, ECG was unremarkable, except for mildly prolonged QTc (480 ms) (Fig. 1B). Baseline electrophysiology study showed sinus rhythm (cycle length 700 ms), normal atrial-His (AH; 76 ms) and His-ventricular (HV; 48 ms) intervals, and absence of VA conduction on pacing from right ventricular (RV) apex at 600 ms. Programmed atrial stimulation showed no dual atrioventricular (AV) nodal physiology. Atrial and ventricular burst and extrastimulation pacing induced the clinical tachycardia easily and reproducibly (Fig. 2A). During the tachycardia (cycle length around 370 ms, HV interval +6 ms), His Bundle (HB) and right bundle (RB) were activated sequentially with a HB-RB interval of 20 ms, which was similar to the HB-RB interval measured during sinus rhythm. Rapid pacing from the RV apex and basal RV septum at cycle length of 360 ms, during the tachycardia, resulted in constant fusion beats, with postpacing intervals exceeding the tachycardia cycle lengths by 154 and 76 ms, respectively. Intravenous bolus of adenosine 18 mg did not affect the

Left hemothorax: A presentation of a late ventricular perforation caused by an active fixation pacing lead

Ventricular perforation, late after ventricular lead placement at the right ventricular apex is rare, and though, commonly presents with chest pain, loss of pacing and/or sensing, and hemodynamic instability caused by cardiac tamponade, it can rarely cause left sided hemothorax needing surgical exploration.

Dilated Cardiomyopathy with Short QT Interval: Is It a New Clinical Entity?

Short QT syndrome is a rare autosomal dominant channelopathy of structurally normal hearts characterized by atrial fibrillation, ventricular arrhythmias, and sudden cardiac death. We report a case having short QT, dilated ventricles, and severe ventricular dysfunction, an unreported association so far.

Late presentation of aortic root abscess in endocarditis with coronary ischemia.

Formation of a large aortic root abscess is an infrequent complication of aortic valve endocarditis in adults. Extrinsic compression of the coronary arteries by this abscess is still rarer. Here, we report a case of a 22-year-old male with aortic root abscess, who presented 2 months after the completion of treatment of endocarditis with exertional angina. Coronary angiogram revealed compression of proximal left anterior descending and left circumflex arteries by the abscess. The patient was successfully treated with pericardial patch exclusion of the abscess cavity and coronary artery bypass graft. The presentation of aortic root abscess with myocardial ischemia as a late complication of treated endocarditis has not been reported earlier.

Bundle branch reentry ventricular tachycardia in arrhythmogenic right ventricular dysplasia

A 42-year-old male had history of recurrent palpitation and was documented to have wide QRS tachycardia. Magnetic resonance imaging angiogram showed evidence of arrhythmogenic right ventricular dysplasia and severe right ventricular dysfunction. Electrophysiology study showed evidence of bundle branch reentry ventricular tachycardia. It was successfully treated by radiofrequency ablation of right bundle branch. This is probably the first case of bundle branch reentry as a mechanism for ventricular tachycardia in a case of arrhythmogenic right ventricular dysplasia.

Carbamazepine-induced sinus nodal dysfunction

Carbamazepine (CBZ) is widely used in clinical practice for various indications. Although its potential harmful effects on the hemopoetic system and liver are well known, the cardiac effects, though rare, have received less attention. This report presents a case of serious, but reversible sinus node dysfunction induced by CBZ in a young male with no structural heart disease. This case highlights the association of CBZ and sinus node dysfunction, which would have resulted in pacemaker implantation in this patient.

Mitral valve surgery: Does it really decrease ventricular arrhythmia in patients with mitral valve prolapse?

Mitral valve (MV) prolapse (MVP) is characterized by fibromyxomatous changes in themitral leaflet tissue, with superior displacement of one or both leaflets into the left atrium. It is not an uncommon finding on echocardiographic screening, afflicting 2e3% of the general population, though most of them remain asymptomatic [1e3]. MVP can be distinguished into primary (nonsyndromic) and secondary (syndromic) MVP. Secondary MVP occurs in the presence of connective tissue disorders such as Marfan syndrome, Loeys-Dietz syndrome, Ehlers-Danlos syndrome, osteogenesis imperfecta, pseudoxanthoma elasticum, and aneurysms-osteoarthritis syndrome. MVP has also been observed in hypertrophic cardiomyopathy (HCM) and may contribute to the pathophysiology of obstruction [1]. MVP is generally regarded as a benign condition [4e6], however, the outcome is widely heterogeneous, and its manifestations such asmitral regurgitation (MR), atrial fibrillation, congestive heart failure, endocarditis, and stroke are well known. Cardiac mortality is best predicted by the presence of mitral regurgitation (MR) and left ventricular dysfunction at the time of diagnosis. Risk factors for cardiac morbidity include age 50 years, left atrial enlargement, MR, the presence of a flail leaflet, and atrial fibrillation [4,7e11]. MR can occur due to a spectrum ranging from single prolapsing valve segment to diffuse myxomatous degeneration with bileaflet prolapse and annular dilatation. Degenerative mitral valve disease, most commonly related to MVP, is the most repairable form of surgical mitral valve disease, and repair is the most recommended surgical approach and represents 60e70% of surgical mitral regurgitation (MR) in industrialized nations [12e15]. Cardiac arrhythmias are frequently detected in patients with mitral valve prolapse (MVP) [16,17]. Atrial ectopics, couplets, atrial tachycardia, paroxysmal or sustained atrial flutter or fibrillation as well as ventricular premature contractions (VPCs), multiform VPC, VPC couplets, and runs of three or more sequential VPCs (salvos of

A case of ‘tachy-brady syndrome’: What is the mechanism?

A young male presented with incessant narrow QRS tachycardia and left ventricular dysfunction. 24-Holter monitoring revealed multiple episodes of sustained and nonsustained episodes of tachycardia with prolonged sinus pauses at termination. The analysis of the electrocardiogram, followed by an invasive electrophysiological study, suggested an unusual mechanism for this tachy-brady syndrome.